Provides caching for AT Protocol identity resolution results.

This module maintains two ETS tables:

• handle_cache: Maps handles to DIDs with TTL
• did_cache: Stores DID documents with TTL

The cache automatically expires entries and provides concurrent access with proper cleanup.

Supervision

ProtoRune is a library and starts no processes of its own. To enable identity caching, add the cache to your application's supervision tree:

children = [
  ProtoRune.Atproto.Identity.Cache
]

When the cache is not running, lookups behave as misses and writes are dropped, so resolution still works (uncached).